1. Technical Field
The present invention relates generally to a security system and method using an automatic meter reading protocol, and, more particularly, to a security system and method using an automatic meter reading protocol, which can solve various problems caused by the operation of a separate security protocol and can be easily implemented and managed.
2. Description of the Related Art
A Device Language Message Specification (DLMS) is an international communication protocol standard for automatic meter reading, which models various types of data treated by meters into logical objects for the purpose of acquiring mutual compatibility, defines data messages using the logical objects as standardized data structures, and prescribes transmission methods of transmitting the data messages to a variety of transmission media.
The DLMS international standard was initiated at International Electrotechnical Commission (IEC) 61107 (FLAG) and IEC 61334-4-41 (distribution line messaging specification), and the fields of use thereof have been widely extended to meter reading fields such as water or gas meter reading, as well as electricity meter reading.
Further, the term “automatic meter reading” refers to a method of reading meter data from individual electricity meters, gas meters, water meters or the like using a terminal at a remote place without a meterman having to personally visit the sites of the customers. The term “automatic meter reading system” refers to a system which automatically collects values indicated by meters, located at the remote place, and details detected by sensors through communication lines based on cables or radio waves, and aggregating or analyzing the collected values and details using a computer.
Such an automatic meter reading system collects information using a telephone line or a power line, or in a Radio Frequency (RF) manner. Further, the automatic meter reading system makes it possible to detect even demand patterns as well as to issue notices in conjunction with computer programs.
In such an automatic meter reading system, a security system for preparing against externally applied security attacks is regarded as a very significant consideration given the fact that the system provides important data that is used for billing for the amount of electricity or the like that is consumed.
In the prior art, separate security protocols which enable meter information to be protected using an authentication method between automatic meter reading devices, a security key management (generation, distribution, update and disposal) method, or the like, have been designed, and there have been presented measures for implementing such protocols.
However, an automatic meter reading and security system using the above prior art has problems such as the addition of security protocols required to generate and manage security keys, factors stemming from the operation of the separate security protocols, for example, an increase in network traffic, in the consumption of resources by devices and in overhead, an increase in device implementation cost stemming from the implementation of an additional security process, and the delay of meter reading stemming from the driving and communication of processes other than a pure meter reading process. Further, the automatic meter reading and security system also has non-negligible problems occurring in the actual implementation of the security system when the resource limitation conditions of a low-performance embedded device (a meter reading device such as a watt hour meter) are considered.
Further, when an automatic meter reading system is constructed, a network management system is additionally constructed for the purpose of efficient management, and power value added services such as integrated meter reading or load management, are added to the same automatic meter reading infrastructure, and thus there is a large concern that there could be an increase in the above-presented problems.
Therefore, a problem arises in that when separate security management protocols are operated, a periodic meter reading failure may be caused by the performance of additional tasks other than automatic meter reading, and this may act as a negative influence on the performance of automatic meter reading which is the original purpose.
Meanwhile, security protocols that have recently been defined by DLMS are divided into protocols for data access security and protocols for data transmission security. Those security protocols are designed such that for data access security, the security types of access to the information of a watt hour meter are divided into three types, that is, unlimited access (no security), low-level access (low-level security), and high-level access (high-level security) and such that for data transmission security, security types are divided into three types, that is, data encryption, data authentication, and data encryption authentication, with the result that the divided protocols are separately operated.
However, in security, the most significant problem to be solved is how to share security information (security keys) among devices. In the first security presented by DLMS, that is, data access security, even if the highest level security is applied, it is impossible to solve the problem of how to share security keys. Since this method enables authentication between devices to be performed using only a password and preset (externally exposed) information, problems may arise in that there are various types of security vulnerabilities, and even methods of sharing security information based on such authentication are not presented.